Data for the publication "To be or not to be – Is MgSc2Se4 a Mg-Ion Solid Electrolyte?"

Description Datasets

Datasets are obtained from X-ray diffraction (XRD), Rietveld analysis, scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), transmission electron microscopy (TEM), nuclear magnetic resonance (MAS NMR) spectroscopy, absorption and photoluminescence spectroscopy, electrochemical impedance spectroscopy (EIS), chronoamperometry (CA) and chronopotentiometry (CP).

Abstract

Magnesium batteries offer promising potential as next-generation sustainable energy-storage solutions due to the high theoretical capacity of the magnesium metal anode. Facilitating dendrite-free operation of metal anodes necessitates the development of solid electrolytes (SEs) with high magnesium-ion conductivity. While the chalcogenide spinel MgSc2Se4 is predicted to exhibit high magnesium ion mobility, unequivocal experimental evidence for magnesium ion conduction beyond short-range motion is still missing. This study confirms magnesium-ion transport in MgSc2Se4 through two independent electrochemical methods: electrochemical deposition of magnesium metal and reversible magnesium plating/stripping cycling. To overcome the difficulty of measuring the ionic conductivity of the mixed conducting MgSc2Se4 spinel, a pure ion conducting interlayer is employed in a symmetric transference cell. This approach effectively suppresses the electron transport, allowing accurate characterization of the ionic conductivity. The experimental results confirm a low migration barrier (Ea) of (386 ± 24) meV for magnesium ion transport in MgSc2Se4 and demonstrate one of the best performances at room temperature among the reported inorganic magnesium solid electrolytes. The findings open a new door for exploring additional mixed magnesium ion conductors and highlight the potential of magnesium chalcogenide spinels as a promising class of magnesium solid electrolytes.

数据集说明
本数据集的数据来源于X射线衍射（X-ray diffraction, XRD）、里特韦尔分析法（Rietveld analysis）、扫描电子显微镜（scanning electron microscopy, SEM）、能量色散X射线光谱（energy-dispersive X-ray spectroscopy, EDS）、透射电子显微镜（transmission electron microscopy, TEM）、核磁共振（nuclear magnetic resonance, MAS NMR）光谱学、吸收与光致发光光谱、电化学阻抗谱（electrochemical impedance spectroscopy, EIS）、计时电流法（chronoamperometry, CA）以及计时电位法（chronopotentiometry, CP）。

摘要
镁金属负极具有极高的理论容量，使得镁电池有望成为下一代可持续储能解决方案。实现金属负极无枝晶运行，亟需开发具备高镁离子传导率的固体电解质（solid electrolytes, SEs）。硫族尖晶石MgSc₂Se₄被预测可表现出优异的镁离子迁移能力，但目前仍缺乏直接实验证据证明其存在长程镁离子传导行为。本研究通过两种独立的电化学方法——金属镁的电化学沉积以及可逆镁电镀/剥离循环，证实了MgSc₂Se₄中的镁离子传输行为。针对混合导电型尖晶石MgSc₂Se₄的离子电导率测量难题，本研究在对称迁移电池中引入纯离子导电中间层，该策略可有效抑制电子传输，从而实现离子电导率的精准表征。实验结果证实，MgSc₂Se₄中镁离子传输的迁移活化能（Ea）为(386 ± 24) meV，且在已报道的无机镁基固体电解质中，其室温性能处于顶尖水平。本研究成果为探索新型混合镁离子导体开辟了新路径，同时凸显了硫族镁尖晶石作为一类极具潜力的镁基固体电解质的应用前景。